1. Field
The present disclosure relates to an apparatus and method for alternative aeration-effluent wastewater treatment using a ceramic membrane, and more particularly, to an apparatus and method for alternative aeration-effluent wastewater treatment using a ceramic membrane, which allows the biological treatment to be performed sufficiently in an intermittent aeration tank by combining an anaerobic tank with a plurality of intermittent aeration tanks and selectively changing an inflow path of influent water according to an operation status of the intermittent aeration tanks and allows the aeration and treated water to continuously discharge through two intermittent aeration tanks by independently forming an air injection line and a treated water discharge line at a ceramic membrane provided in each intermittent aeration tank.
2. Description of the Related Art
At this point in time where environmental problems are discussed as global issues, the desire for high-quality and safe water and agreeable hydrological environments is increasing day by day. Even though an existing sewage function was subjected only to removing organic substances, the sewage function has been improved by applying an advance treatment technique including removal of nitrogen and phosphorus. In addition, it is expected that the importance on the advancement of sewage function will continuously increase in the future in order to ensure quality and safety of water sources such as lakes and rivers.
The advanced treatment technique is classified into physicochemical treatment, biological treatment, and complex treatment using both physicochemical treatment and biological treatment. The physicochemical treatment uses coagulative precipitation, separation, adsorption, ion exchange, oxidation or the like, and the biological treatment representatively uses aerobic treatment, anaerobic treatment, a combination of aerobic treatment and anaerobic treatment or the like. The complex treatment is a water treatment technique having multiple unit processes such as physicochemical and biological treatment stages.
Biological advanced processes basically use an active sludge process, but anaerobic, anoxic and aerobic conditions or reaction tanks are suitably combined and used in order to remove nitrogen and phosphorus. In Korea, about fifty modified biological advanced processes have been developed.
An A2/O process, a 5-stage Bardenpho process, a UCT process, a VIP process, a sequencing batch reactor (SBR) or the like are most basically used to remove nitrogen and phosphorus. Recently, a process using a membrane bio reactor (MBR) has been proposed, and the MBR process solves problems of existing biological treatment such as sludge bulking since the MBR process requires a small installation area, allows easy automatic operation and does not demand operating a separate precipitation tank. In addition, the quality and amount of water to be treated may be adjusted according to material of the membrane and surface characteristics such as pores, and a RO membrane may be further used at the rear end selectively to perfectly remove a trace of harmful antibiotic or medicinal substances. For this reason, the MBR process is frequently used as a reutilization process. The demand for the advance treatment of sewage and waste water using the MBR is rapidly increasing along with the water reutilization policy, and a system combined with a biological nitrogen and phosphorus removing process is being developed.
Recently, the Minister of Environment in Korea has integrated an existing Wastewater and Excreta Act into a Sewage Act System, and the revised and proclaimed Sewage Act was enforced on September, 2007. Main changes of the newly enforced Sewage Act include reinforced water quality criteria on water discharge and obligations about reutilization of treated water to the public sewage treatment facility to promote the use of water recycling. According to this Act, for wastewater treatment facilities having a daily treatment capacity of 50 m3 or above, the criteria on the quality of discharge water is reinforced to the same level as the public sewage treatment facilities to obey 10 mg/L or less of BOD and SS, 20 mg/L or less of entire nitrogen, 2 mg/L or less of entire phosphorus, 3,000 or less per mL of colon bacillus. The revised Act is applied to existing facilities from Jan. 1, 2012. Therefore, it is expected that the market for advanced biological treatment methods combined with the MBR system, which are suitable for small-sized sewage treatment facilities, will rapidly increase.
Korean Patent Registration No. 275563 discloses a wastewater treatment apparatus having an anaerobic tank and two intermittent aeration tanks, and an aerobic condition and an anoxic condition are alternately applied in two intermittent aeration tanks to remove nitrogen and phosphorus. However, even though Korean Patent Registration No. 275563 is applied, it is difficult to meet the gradually reinforced water quality criteria. In addition, when reutilizing treated water, a filtering process should be added, or a membrane or a separate membrane separating tank is additionally required in the intermittent aeration tank.